An unloading apparatus is arranged to direct material to a container. A controller determines a build-up speed of the material in the container； in accordance with the determined build-up speed, determine a rate of change to be applied when setting an attribute of at least one of the unloading apparatus and container； and set an attribute of at least one of the unloading apparatus and container in accordance with the determined rate of change in order to direct the material from the unloading apparatus to the container.
